JSON to Zod Schema Generator

Why generate Zod from JSON?

Zod has become the default validation library for TypeScript because a single schema gives you both runtime checks and a static type via z.infer. Hand-writing schemas for a large API response is tedious and error-prone. Generating from a real payload captures the exact shape you receive — fields, nesting, and array element types — as a correct starting point.

This matters more now that the widely used json-schema-to-zod project is winding down, leaving a gap for simple, maintained JSON-to-Zod tooling.

What the generator produces

Each JSON object becomes a named, exported Zod schema; nested objects are emitted as their own schemas so the output stays readable and reusable. Integers use z.number().int(), decimals use z.number(), and arrays become z.array(...) — with z.union(...) when the elements are mixed. A final z.infer type is exported for the root schema.

• z.object for objects, z.array for arrays
• z.string, z.number().int(), z.number(), z.boolean, z.null
• Named schemas for nested objects, defined child-first
• An inferred TypeScript type via z.infer<typeof Schema>

Zod schema vs plain TypeScript types

A TypeScript interface documents a shape at compile time but disappears at runtime, so it can't validate data crossing a boundary (an API response, form input, or LLM output). A Zod schema validates at runtime and derives the type for free. If you only need types, the JSON to TypeScript tool is lighter; if you need to parse and validate untrusted data, Zod is the better fit.

Refine before production

Generated schemas mirror one sample, so tighten them for real contracts: mark optional fields with .optional(), add .email(), .url(), .min()/.max(), or .uuid() where appropriate, and replace permissive unions with .enum() when a field has fixed values. Treat the output as a scaffold you refine, then use schema.parse() or safeParse() at your boundaries.